This invention relates to a fitting for mounting to the ends of smooth wall tubes.
The fitting of the present invention is generally related to those types of fittings disclosed in U.S. Pat. Nos. 3,738,688; 3,779,587; and 3,868,132.
The fittings disclosed in the above-mentioned U.S. patents are mounted to the end of a smooth wall tube by, generally, compressing a tubular plug against the outer diameter of the tube upon translation of a ram element within the housing thereof. Such fittings provide a good seal and holding action so that fluids passing through the smooth wall tube may be sealed by the fitting, or may be conveyed out of the fitting into auxiliary tubing mounted thereto.
While these fittings function exceptionally well in most cases, the fitting of the present invention is particularly designed for application on short protrusion or expanded refrigeration and air conditioning tube ends existing on all industrial components, such as, for example, condensers, evaporators, compressors, header assemblies and the like. In many cases, the tubing is thin-walled, and fittings of the type disclosed in the above-identified U.S. patents can distort the tube ends when fitted thereto.
Accordingly, the present invention provides such a fitting that not only grips on the outside diameter, but also seals on the inside diameter. The counter forces of ID sealing and OD gripping at the same point eliminate the possibility of tube distortion especially on minimum wall tubing even at elevated pressures.
In the application of the fitting, only a short protrusion is required, generally only about 0.200", for tubes up to 0.625" OD. The fitting is applicable for use on a wide range of tube sizes, for example, from 0.250"ID and 1.00"OD. Due to the limited tube length required, maximum area of tube may be tested, and testing may be done above the support plate on a condenser or evaporator core. The fitting's configuration, furthermore, is designed for confinement clearance side-by-side use on condensor and evaporator cores, as well as compressor body clearance. Simple maintenance of the fitting is all that is required.
Accordingly, it is an object of the present invention to provide improved fittings for mounting to the ends of smooth wall tubes. More particularly, it is an object to provide such a fitting which is designed for application on short protrusions or expanded tube ends, and which seals on the inside diameter (ID) and grips on the outside diameter (OD), at the same point, thus eliminating tube distortion.